Road composition



Patented Dec. 1, 1931 No Drawing.

PATENT OFFICE SAMUEL s. sAnrLnn, or SPRINGFIELD TOWNSHIP, MONTGOMERY COUNTY, AND EUGENE. F. GAYO, or. PHILADELPHIA, PENNSYLVANIA, nssrenon TO AMIESIT'E ASPHALT COMPANY OF AMEBIOA, or PHILADELPHIA, PENNSYLVANIA, A: CORPORATION OF .NEW JERSEY gate, and the principal object of the inven-j tion is to provide a novel method for forming a bitumen road composition using anundried orwet aggregate, whereby the expenslve drying operatlon normally requlred 1n order to effect a close bond between the aggregate and the bitumen may be eliminated. In the buildingof roads of this type, the stone aggregate invariably is received in a damp and often Wet condition, and although in certain types of road stone in this condition has been mixed with asphalt or other bitumen, roads so made. lack cohesion and close union between the aggregate and the bitumen and are therefore unstable. I It accordingly is customary in making the better grades of road and road compositions to dry the aggregate and to free it of all or the greater part of its moisture content.

In one type of road it also is highly desirable to obtain in the stone .aggregate an absorption and storage of an appreciable amount of a bitumen solvent, this having among other desirable effects that of rendering the curing process of the finished road a comparatively slow one, The use of damp or wet stone as ordinarily used positively precludes the possibility of getting this desirable storage effect, and this fact has resulted again in a requirement for an extensive preliminary drying of the aggregate.

' Ttis the principal object of this invention therefore to provide a commercially practicable method for obtaining a thorough bond between the aggregate and the bitumen withv. out a predrylng operation regardless of the amount of moisture present, and also under similar conditions to obtain,'where desired, the aforesaid storage in the aggregate of a bitumen solvent; I 1

In carrying out our invention,we preferably thoroughly wash the stone aggregateby spraying with warm water, this having the multiple effect of cleaning out the fines and dust, bringing the entire aggregate to a uniform condition of wetness, and raising the temperature of the wet stone to a moderate Roan COMPOSITION Application filed September 15, 1926. Serial No. 135,702. 1

temperature of say 95 F. In some in stances, it maybe desirable to retain the fines, and in such cases provision may be made either for preventing their removal or for reincorporating them in the aggregate.

We then take the wet and preferably warm stone and'thoroughly mix with it by any'suit ablemeans a'quantity of a soluble soap,such

for example as saponified sulfonated 'oil, 'orI any commercial soap, which may be incorpo rated either in a powdered and dry condition, or in liquid form. The quantityof soap employed may vary widely, although we have found satisfactory, approximately one pound of the soap to each ton of aggre gate. When this soap has been thoroughly incorporated and mixed with the aggregate, we add a quantity of a more or less volatile bitumen solvent, such as kerosene, gasoline or the like, and agitate the mass. The quantity of this solvent may vary largely, although for general purposes about two gallons per ton of aggregate will be found suflicient. This solvent formswith thewaterand the soluble soap an emulsion 'of the oil i'nwater type, in which the water isthe'continuous element, and we thereby replace the water in the interstices and pores of'the stone and onthe surface thereof'with the water mixing operation we temporarily liquefy the ,4,

asphalt, preferably by heating; a temperature of about 240 F. ispreferred. Although it is preferred to use heat as the liquefying agent,'the desired result may be effected othermeans, as by adding to the bitumen a suitable volatile solvent or liquefier such asgasoline. Where a solvent is used as the; liquefying agent, Y the solvents originally added to the aggregate may be dispensed with. In this event, however, at lea'sta part of the solvent or liquefier used preferably is freed from the emulsion, separates from the" mass soon after the lime. is added.

As an actual preferred example of our process, we may take 1900 pounds of wet stone aggregate free from fines and dust and preferably at a temperature of about 95 F., and add thereto approximately one pound of saponified sulfon'ated oil, thoroughly mixing and incorporating this soap in the aggregate. e now add about two gallons of approximately 50% mixture of kerosene and naphtha, and following the mixing in of these solvents, we add to the aggregate asphalt in amount to thoroughly coat the individual stones, the asphalt being in fluid state and at a temperature of about 240 F., and rapidly incorporate it by stirring. Generally, asphalt in amount equal to 5% by weight of the aggregate will be sufficient.

Thereafter, we preferably add lime in amount approximately eight pounds per ton batch of the bitumen-stone composition.

By this process we are able to provide an asphaltic road in which the individual stones are thickly and with substantial permanency coated with the bitumen. The aggregate also retains in temporary storage an appre-. ciable amount of the kerosene, retarding the final set of the composition after it has been'laid upon the roadbed. Of primary importance, however, the process provides for the use of wet stone in the manufacture of bitumen road compositions without special drying operations, and thereby creates a material saving.

It will be understood that the process may be varied to some extent from that outlined above without departure from the invention. It is possible for example as suggested above to add the bitumen solvent and the bitumen simultaneously either individually or in the form of a mixture previously prepared. In fact, the benefits of the invention may be realized to some extent by adding the bitumen in advance of the liquefier. There may also be some variation as to the addition of the emulsifying agent, since it is not strictly essential that this be added directly to the. wet,

stone in advance of the other elements. There also is to be no strict limitation as to the relative proportions of the various materials used, since these also may vary in large degree. The procedure and proportions demen.

2. The method of forming a road composition, which consists in mixing with a stone aggregate in moist condition and many sequence or order a bitumen solventincluding kerosene, an agent adapted to form an oilin-water emulsion with the said solvent and the moisture content of the stone, and a temporarily liquefied bitumen, and when the aggregate is coated with said ingredients adding to the mixture an ingredient operative to break the emulsion.

3. The method of forming a road composition, which consists in mixing with a stone aggregate in moist condition and in any order or sequence a bitumen solvent consisting ofa 50% mixture of kerosene and naphtha, an agent adapted to form an oil-in-water emulsion with the said solvent and the moisture content of the stone, and a temporarily liquefied bitumen, and subsequently adding an alkaline earth ingredient to break the emulsion.

4. The method of forming a road composition, which consists in adding directly to a stone aggre ate in moist condition an agent adapted to orm an oil-in-water' emulsion with a subsequently added solvent of bitumen and the moisture content of the stone, and thereafter adding the said solvent, and a temporarily liquefied bitumen, and subsequently adding an ingredient to slowly break the emulsion.

5. The methodof forming a road composition, which consists in adding directly to a stone aggregate in moist condition an agent adapted to form an oil-in-water emulsion with a subsequently added solvent of bitumen and the moisture content of the stone, thereafter adding the said solvent, and a temporarily liquefied bitumen, and subsequently adding an alkaline earth ingredient operative to slowly break said emulsion.

6. The method according to claim 1, in which the elements employed are proportionately as follows stone aggregate 1900 lbs., bitumen 100 lbs. of asphalt, solvent 1 to 2 gallons of a 50% mixture of kerosene and naphtha, emulsifying agent 1 lb. of saponified sulfonated oil, and 6 to 10 lbs. of lime.

7. The method of forming a road composition, which consists in mixing with a mineral aggregate in a moist condition and in any sequence or order, a bitumen solvent, an agent adapted to form an oil in' water emulsion with said solvent and the moisture content of said aggregate, and a temporarily liquefied bitumen, and subsequently adding thereto an ingredient operative to break said emulslon.

8. The method of forming a road composition, which consists in mixing with a mineral aggregate in a moist condition, a bitumen solvent, a Water-soluble soap adapted to form an oil in Water emulsion With said solvent and the moisture content of the aggregate, and a temporarily liquefied bitumen, and thereafter adding to the mixture, an agent operative to convert said Water-soluble soap into a Water-insoluble soap.

SAMUEL S. SADTLER. EUGENE F. CAYO. 

